考虑流变—损伤与损伤恢复的盐岩储库变形与稳定性研究

发布时间：2018-09-15 19:04

【摘要】：盐岩是一种比较特殊的软岩,与普通岩石相比,有更加特别的性质:结构致密、塑性变形能力强,渗透率极低、良好的蠕变行为和损伤自愈等特性,被国际上公认为是石油、天然气储备和放射性废物处置的理想场所。盐岩储气库的密封性能是储气库的一项重要技术和安全指标,由于流变损伤的作用,层状盐岩储气库极可能会因为变形和稳定问题,造成天然气的外部渗漏。针对我国盐矿具有多夹层和多杂质的特点,本文编写userc_d_h流变损伤恢复程序,依托ANSYS二次开发分析研究了流变损伤和损伤恢复作用对层状盐岩洞室稳定性的影响。首先,通过已知的盐岩流变损伤试验,研究盐岩的流变损伤特性,盐岩变形从局部破坏到总体失稳,其实质是盐岩损伤不断发展积累的过程;而盐岩损伤恢复过程,则对应其蠕变速率不断降低的过程。其次,基于王贵君教授的流变损伤模型userc_d,编写开发了流变损伤恢复模型userc_d_h。程序使用FORTRAN语言,融合有限元软件ANSYS的二次开发技术,具有操作简单、可靠性高的特点。再次,应用自主开发的userc_d_h模型,对具有试验结果的麦金托什盐丘盐岩蠕变试验进行验证。加载程序模拟实际的试验加载过程即三轴加载,圆柱试件的数值模型运算结果与试验结果吻合很好,验证了程序的可用性。最后,将开发的userc_d_h应用于使用ANSYS软件建立的盐岩储库几何模型中。采用userc_d与userc_d_h两种本构模型对比分析盐岩洞室在变形、应力分布区域及损伤、蠕变分布区域的差异,得出应用userc_d_h的洞室模型在卸压时出现了盐岩蠕变曲线斜率明显降低的现象,不同卸压斜率降低程度不同。采用userc_d_h模型更准确的描述了盐岩变形的规律,这对维护洞室的稳定,防止灾变的发生大有裨益。创新点:对盐岩洞室的变形和稳定性分析加入了损伤恢复作用,借助ANSYS软件的二次开发功能模拟了洞室的损伤以及对洞室进行卸压时盐岩的损伤恢复现象。
[Abstract]:Salt rock is a kind of special soft rock. Compared with ordinary rock, salt rock has more special properties, such as dense structure, strong plastic deformation ability, extremely low permeability, good creep behavior and self-healing of damage, etc., which is recognized as oil in the world. Ideal place for gas storage and radioactive waste disposal. Sealing performance of salt rock gas storage is an important technical and safety index of gas storage. Due to the effect of rheological damage, stratified salt gas storage is likely to cause external leakage of natural gas due to deformation and stability. In view of the characteristics of multi-intercalation and multi-impurity in salt mines in China, the userc_d_h rheological damage recovery program is compiled, and the influence of rheological damage and damage recovery on the stability of layered salt caverns is studied by means of secondary development of ANSYS. First of all, through the known salt rock rheological damage test, the rheological damage characteristics of salt rock are studied. The salt rock deformation from local failure to total instability is essentially the process of salt rock damage development and accumulation, while the salt rock damage recovery process. It corresponds to the process of decreasing creep rate. Secondly, based on Professor Wang Guijun's rheological damage model userc_d, the rheological damage recovery model userc_d_h. is developed. The program uses FORTRAN language and combines the secondary development technology of finite element software ANSYS. It has the characteristics of simple operation and high reliability. Thirdly, the creep test of salt rock in Macintosh salt mound with experimental results is verified by using userc_d_h model developed by ourselves. The loading program simulates the actual experimental loading process, that is, triaxial loading. The numerical model results of the cylindrical specimen are in good agreement with the experimental results, and the availability of the program is verified. Finally, the developed userc_d_h is applied to the geometric model of salt reservoir established by ANSYS software. The difference of deformation, stress distribution, damage and creep distribution of salt rock cavern is analyzed by using userc_d and userc_d_h constitutive models. It is concluded that the slope of creep curve of salt rock decreases obviously when userc_d_h model is used to relieve pressure. The slope of different pressure relief is different. The userc_d_h model is used to describe the law of salt rock deformation more accurately, which is helpful to maintain the stability of the cavern and prevent the occurrence of catastrophe. Innovation: damage recovery effect is added to the deformation and stability analysis of salt rock cavern. The damage and recovery phenomenon of salt rock is simulated by the secondary development function of ANSYS software.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE972

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